In the meat packing industry, techniques are known for the automatic and semiautomatic filling of various types of casings with viscous meat emulsion. In general, these techniques include positioning a shirred continuous film casing length over a stuffing horn and thereafter continuously deshirring the casing and stuffing the deshirred casing with viscous meat emulsion fed under pressure through the stuffing horn and into the casing interior. As used herein, the term "casing" or "tubular casing" is intended to mean tubing of natural or manufactured materials, and the term "casing length" is intended to mean continuous tubular casing lengths. Shirred tubular casings are also known to persons familiar with the art as "sticks", such "sticks" being long lengths of casing having a substantially large bore, which have been shirred and compressed into short compact self-sustaining lengths, or which may be a package of shirred and compressed casing sheathed inside a retaining sleeve, or mounted on a semirigid retaining tube. Using suitable food stuffing machinery, casing lengths can be stuffed and formed into unit size packages of particulate viscous materials, such as ground or chopped fresh meats, or the like. It is to be understood that the invention is not limited to such stuffed products, but is equally advantageous for the encasing of stuffed products of viscous material, such as fats, cheese, ice cream, scrapple, meat products, as well as lard, oleomargarine, grease and other products normally stuffed into casings.
The materials from which the casing lengths discussed herein are manufactured are typically thin-walled, flexible thermoplastic films prepared from polyethylene and other polyolefins, polyvinylidene chloride, polyvinyl chloride, polyesters and the like, or they may be prepared from unsupported or fibrous reinforced cellulose, or any other suitable material. Apparatus and processes are well known in the food casing art for shirring tubular cellulosic food casing, such as, for example, disclosed in U.S. Pat. Nos. 2,983,949 and 2,984,574 to Matecki. These apparatus may be employed in the preparation of pleated and compressed tubular casings wherein the compression ratios (unshirred to shirred stick length) are in the order of at least about 40:1 and up to about 100:1 or even greater.
In the art of producing sausages and similar food products, finely divided meat compositions commonly referred to as emulsions are conventionally stuffed into tubular material of long length which, as stated above, may be of natural or manufactured materials. The stuffed tubing is then tied, twisted or clipped into predetermined unit length packages. For many years, the apparatus and methods employed to prepare the encased food products and particularly food products encased in large diameter casings have relied upon manual manipulation in controlling the stuffing of food emulsion into predetermined length sausage links or packages. Recently advances in the art have resulted in the introduction of apparatus for machine control of the stuffing operation which have provided means for preparing uniformly sized encased food products as, for example, disclosed in U.S. Pat. Nos. 2,871,508, 2,999,270, 3,264,679, 3,317,950, 3,454,980, 3,457,588, 3,553,769, 3,621,513, 3,659,317 and 3,751,764.
Of the most recent advances in the art, several satisfactory methods and apparatus are available for sausage production in the smaller diameter and length sizes, frankfurters particularly, and also for the production of stuffed casing in the larger diameter and length sizes, such as bologna, salami, liverwurst and the like products.
Although many of the prior art stuffing apparatus can generally provide an overall fairly good stuffed article, one problem generally encountered in many of the apparatus is that after the product flow is stopped and the stuffed casing is advanced to a clip closing station, strands of the product, such as meat strands, can drag along the inside of the casing and become entrapped within the clip-closure zone. In the stuffing of meat emulsion, the entrapped meat strands within the clip closure zone can cause a non-liquid type closure, bacterial spoilage of the meat emulsion, and, in addition, provide an unsightly commercially unacceptable stuffed article.
It is, therefore, an object of the present invention to provide an apparatus for stuffing a shirred or unshirred casing so as to produce a stuffed casing having product-free closure zones.
Another object of this invention is to provide a stuffing apparatus with a product stoppering means which is capable of stopping product flow into a casing and then severing and compacting the product at the trailing end of the casing so as to provide an effective product-free closure zone at the trailing end of the stuffed casing adjacent the stuffed product.
Another object of this invention is to provide a method for producing a stuffed product casing having product-free closure zones.
These and other advantages and features of the present invention will become apparent from the ensuing description and from the accompanying drawing.